Tank maintenance access chamber

ABSTRACT

A fuel storage system has a tank access chamber with improved monitoring, servicing and maintenance capabilities. In particular, the chamber includes a sump monitored by a liquid sensor whose proper function can be automatically checked remotely, e.g., via an electronic controller or remote manual operation. In cases where such a check indicates a need for physical inspection of the sump sensor, the present system provides for sensor removal and installation by service personnel from a location outside the tank access chamber. Thus, the present system facilitates regular inspection and routine or unplanned maintenance without the need for a person to physically enter the tank access chamber.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims the benefit under Title 35, U.S.C.Section 119(e) of U.S. Provisional Patent Application Ser. No.62/212,943, filed Sep. 1, 2015 and entitled “Un-manned maintenance TankAccess Chamber,” the entire disclosure of which is hereby expresslyincorporated herein by reference.

BACKGROUND 1. Technical Field

The present disclosure relates generally to a tank access chamber of afueling system and, more particularly, to a tank access chamberconfigured to facilitate inspection and maintenance of the equipmentcontained therein without the need for a person to physically enter thetank access chamber.

2. Description of Related Art

Tank access chambers or sumps may be included in fueling systems tocontain and protect the fuel system equipment positioned at the tankmanway lid and allow it to be accessed for inspection, maintenance andrepair. Such access chambers also function to contain fuel leaks to thechamber, thereby preventing release into the surrounding environment.Similarly, such access chambers also prevent water ingress frons thesurrounding environment into the chamber and fueling system.

Current tank access chambers provide containment for Fuel systemequipment. In some cases, a service technician desiring to performinspection, maintenance and/or repair of equipment within the tankaccess chamber must physically enter the tank access chamber, e.g., byclimbing below grade and into the cavity of the chamber, in order toaccess the equipment of interest.

Additionally, such equipment is often supplied by various manufacturers,such that compatibility between the interconnected components is notguaranteed. In some cases, this lack of compatibility may impair thefunction or working life of the service station.

SUMMARY

The present disclosure provides a fuel storage system with a tank accesschamber having improved monitoring, servicing and maintenancecapabilities. In particular, the chamber includes a sump monitored by aliquid sensor whose proper function can be automatically checkedremotely, e.g., via an electronic controller or remote manual operation.In cases where such a check indicates a need for physical inspection ofthe sump sensor, the present system provides for sensor removal andinstallation by service personnel from a location outside the tankaccess chamber. Thus, the present system facilitates regular inspectionand routine or unplanned maintenance without the need for a person tophysically enter the tank access chamber.

In addition to such monitoring and maintenance functions, the presentfuel storage system may also include strategic system redundancies,e.g., dual-wall storage tanks, service lines and fill ports.Individually and collectively, these systems and structures cooperate toensure long term performance of the fuel storage system while preventingleaks and providing built-in protection for system users and servicepersonnel.

In one form thereof, the present disclosure provides a control assemblyfor a fuel system including a sump, the control assembly comprising: asensor having a distal end disposed within the sump, the sensorproviding a liquid presence indication responsive to a liquid in thesump being at least at a threshold liquid level; a controller operablyconnected to the sensor and receiving the liquid presence indication;and a testing device operably connected to the sensor, the testingdevice comprising a distal actuator having a service configuration and atesting configuration, and a proximal control drivingly connected to thedistal actuator, wherein actuation of the proximal control toggles thedistal actuator between the service configuration and the testingconfiguration, and wherein in the testing configuration the distalactuator changes a physical configuration of the sensor to cause thesensor to provide the liquid presence indication when the liquid isbelow the threshold liquid level.

In another form thereof, the present disclosure provides a method ofassessing a function of a sensor, the method comprising: installing asensor in a sump of a fuel dispensing system, such that the sensorextends downwardly into the sump to monitor for fluid infiltration ofinto the sump; and after installing, assessing the function of thesensor without physically accessing the sump.

In another form thereof, the present disclosure provides a fuelingsystem assembly comprising: a sump; a sensor having a distal enddisposed within the sump, the sensor defining an actuated physicalconfiguration indicative of the presence of liquid within the sump at orabove a threshold level and a non-actuated physical configurationindicative of the absence of liquid within the sump at or above thethreshold level; a magnetic sensor retainer fixed adjacent the sump viaat least one magnet received on a ferromagnetic surface, the magneticsensor retainer having the sensor affixed thereto.

In yet another form thereof, the present disclosure provides a fuelingsystem assembly comprising: a sump; a sensor having a distal enddisposed within the sump, the sensor defining an actuated physicalconfiguration indicative of the presence of liquid within the sump at orabove a threshold level and a non-actuated physical configurationindicative of the absence of liquid within the sump at or above thethreshold level; a remote sensor locator fixed adjacent the sump, theremote sensor locator defining a funnel-shaped guide cavity having anaperture at a distal end sized to snugly receive the correspondingdistal end of the sensor, and a proximal end sized to receive the distalend of the sensor with substantial clearance.

BRIEF DESCRIPTION OF THE DRAWINGS

The above mentioned and other features and advantages of thisdisclosure, and the manner of attaining them, will become more apparentand the invention itself will be better understood by reference to thefollowing description of embodiments of the invention taken inconjunction with the accompanying drawings, wherein:

FIG. 1 is a cross section, elevation view of a tank access chamberassembly made in accordance with the present disclosure, shown in abelow-grade installation with an underground storage tank;

FIG. 2 is a perspective view of a liquid sensor positioned to detectfluid entry within a sump of the tank access chamber assembly shown inFIG. 1, in which the sensor is held in place by a magnetic sensorretainer;

FIG. 3 is a perspective, exploded view of the magnetic sensor retainershown in FIG. 2;

FIG. 4 is an elevation, cross section view of the magnetic sensorretainer shown in FIG. 3, taken along the line IV-IV of FIG. 3, and withthe retainer fully assembled as shown in FIG. 2;

FIG. 4A is a perspective view of a magnetic module retainer made inaccordance with the present disclosure, in which a module is attached toa manifold via the module retainer;

FIG. 5 is a cross section, elevation view of the sensor, sump, andretainer of FIG. 2, shown with an extraction tool engaging the sensorretainer;

FIG. 6 is another perspective view of the sensor, sump, and retainer ofFIG. 5, in which the extraction tool has disengaged the retainer fromits seated position;

FIG. 7 is a perspective view of a scoop-shaped sensor locator made inaccordance with the present disclosure, illustrated in an installedconfiguration adjacent a liquid sump and with a sump liquid sensorinstalled therein;

FIG. 8 is another perspective view of the sensor, sump, and scoop-shapedsensor locator shown in FIG. 7, in which the liquid sensor has beendisengaged from the sensor locator;

FIG. 9 is a cross section, elevation view of a distal end of a sumpliquid sensor made in accordance with the present disclosure, includinga first test actuation mechanism;

FIG. 10 is a cross section, elevation view of a distal end of a sumpliquid sensor made in accordance with the present disclosure, includinga second test actuation mechanism;

FIG. 11 is a cross section, elevation view of a distal end of a sumpliquid sensor made in accordance with the present disclosure, includinga third test actuation mechanism;

FIG. 12 is a perspective view of a sump liquid sensor made in accordancewith the present disclosure, including a cable-operated sensor tester;

FIG. 13 is a cross section, elevation view of a distal portion of thesensor shown in FIG. 12, illustrating the sensor tester in anon-actuated configuration;

FIG. 14 is another cross section, elevation view of the sensor shown inFIG. 13, in which the sensor tester is in an actuated configuration;

FIG. 15 is a cross section, elevation view of a swing arm-operatedsensor tester made in accordance with the present disclosure, includinga liquid sensor in a monitoring position within a sump;

FIG. 16 is another cross section, elevation view of the swingarm-operated sensor tester shown in FIG. 15, in which the tester hasbeen swiveled toward a sensor test position;

FIG. 17 is a cross section, elevation view of another swing arm-operatedsensor tester, with a sump liquid sensor in a monitoring position withina sump;

FIG. 18 is another cross section, elevation view of the swingarm-operated sensor tester shown in FIG. 17, with the sensor swiveledinto a sensor test position;

FIG. 19 is a cross section, elevation view of a cam-operated sensortester made in accordance with the present disclosure, having a sumpliquid sensor in a monitoring position within a sump;

FIG. 20 is a cross section, elevation view of a cam shaft and sensorhousing of the cam-operated sensor tester of FIG. 19, taken along theline XX-XX of FIG. 19;

FIG. 21 is a cross section, elevation view of the cam shaft and sensorhousing of the cam-operated sensor tester shown in FIG. 19, taken alongthe line of XXI-XXI of FIG. 19, with the sensor in a monitoringconfiguration;

FIG. 22 is another cross section, elevation view of the cam shaft andsensor housing shown in FIG. 21, in which a cam lobe of the cam shafthas lifted the sensor from its monitoring position;

FIG. 23 is another cross section, elevation view of the cam shaft andsensor housing shown in FIG. 21, in which the sensor has been rotatedinto the sensor test position via interaction between a cam shaft keyand corresponding sensor housing notch;

FIG. 24 is a cross section, elevation view of another cable operatedsensor tester, in which the sensor is shown in its monitoring positionwithin a sump;

FIG. 25 is a perspective view of the cam operated sensor tester shown inFIG. 24, illustrating an off-center sensor housing pivot; and

FIGS. 26-28 are block diagrams depicting operation of an embodiment of aliquid sensor operably coupled to a testing device.

Corresponding reference characters indicate corresponding partsthroughout the several views. The exemplifications set out hereinillustrate exemplary embodiments of the invention, and suchexemplifications are not to be construed as limiting the scope of theinvention in any manner.

DETAILED DESCRIPTION

The present disclosure provides tank access chamber assembly 10, shownin FIG. 1, including a sensor 12 which monitors a sump 18 for fluidingress within the tank access chamber 22. As described in detail below,sensor 12 is actuated by the presence of a threshold level of fluid insump 18, but may also be remotely actuatable, manually and/orautomatically, in order to check and verify proper sensor function, viaany of a number of remote actuation mechanisms. Sensor 12 may also beheld in place adjacent sump 18 by magnetic sensor retainer 40 (FIG. 2),and/or may be guided into a proper position and orientation by sensorlocator 60 (FIG. 8). In instances where it is determined that sensor 12must be physically retrieved from tank access chamber 22, extractiontool 50 (FIG. 5) or other retraction device may be provided to disengagethe strong magnetic attachment provided by retainer 40 to facilitateretrieval of sensor 12 without the operator having to physically entertank access chamber 22. For purposes of the present discussion, tankaccess chamber 22 is described and illustrated with respect to, e.g.,monitoring and retrieval of sensors such as sensor 12. However, it isalso contemplated that other fuel system chambers or cavities, such asthe interior of a spill containment system for example, may also be usedin connection with the technologies described herein.

In the exemplary embodiment of FIG. 1, tank access chamber assembly 10has a fuel intake pipe 14, commonly referred to as a filling line, whichreceives fuel from an outside source (e.g., a fuel tanker truck) andtransfers the fuel to underground storage tank 100. Typically, pipe 14extends to or near the bottom of tank 100. Assembly 10 also includes afuel discharge pipe 16, commonly referred to as a product delivery line,which withdraws fuel from the bottom of tank 100 and discharges the fuelto an end user, e.g., a customer using a fuel station pump to fuel avehicle. Pipes 14, 16 pass through sidewall 38 of tank 20, and throughmanway lid 30 received in manway riser 26. A pump is used to withdrawfuel from tank 100 via discharge pipe 16, such as a submersible pumplocated at or near the bottom of tank 100 which pressurizes fuel withinpipe 16, or a dispenser pump located outside tank 100 which createssuction within pipe 16. A tank collar 24 extends from the outer wall ofstorage tank 100 to tank 20, forming sump 18.

In some applications, a monitoring system may be in fluid communicationwith a vacuum generator, which is monitored by a secondary containmentcontrol module 110 as further described below. Generally speaking andfor simplicity of FIG. 1, tank access chamber assembly 10 is shown withfewer systems than might be used within chamber 22. Of course, any andall additional systems described herein may be also used in connectionwith assembly 10, including a submersible pump manifold 111 inconnection with module 110 (see also FIG. 4A), a vent pipe 34 used forpreventing undue pressure buildup in tank 100, and other systems.

Tank 20 is installed below grade G, with riser 102 extending upwardlyfrom the upper end of tank 20 to just below grade G. A gravel guard 101may be provided around the proximal periphery of riser 102, as shown. Asub-grade lid 104 is received on a proximal end of riser 102, and insome installations, may have a transparent viewing port 108 formedtherein for visual inspection of tank access chamber 22 without removingsub-grade lid 104. A grade-level lid 106, commonly referred to as anaccess cover, is received in a concrete support ring to protect tankaccess chamber assembly 10 from vehicles and the like.

For purposes of the present disclosure, “distal” structures areconsidered to be relatively further from a user or operator of assembly10 who is positioned at or above grade G as shown in FIG. 1, while“proximal” structures are considered to be relatively closer to such auser. For example, when sensor 12 is in the installed configuration ofFIG. 1 and monitoring sump 18 for fluid as described below, the distalend of sensor 12 is the “bottom” portion of the sensor further fromgrade G, while the proximal end of sensor 12 is the “top” portion ofsensor 12 closer to grade G.

For purposes of the present disclosure, a “fuel pipe” is a pipe suitablefor the transmission of hydrocarbon fuels, such as gasoline and diesel.Fuel pipes are suitable for use with such materials, and are designedfor safe operation in potentially explosive atmosphere. Fuel pipes maybe made of certain exemplary materials such as High Density Polyethylenelined with Ethyl Vinyl Alcohol, Nylons, fiberglass or metal. Moreover,suitable fuel pipes may be produced from hydrocarbon-resistant materialsand may be made with an internal anti permeation layer to ensurehydrocarbon materials cannot leach through the wall of the pipe.Polymeric pipes are generally multi-layered to achieve a combination ofstrength and flexibility and permeation resistance. Suitable materialsmay include thermoplastics, thermoset materials and steel, for example.

1. Magnetic Sensor Brackets

Turning to FIG. 2, magnetic sensor retainer 40 is shown with liquidsensor 12 affixed thereto via adjustable clamps 44 which attach to body42 of retainer 40 and wrap around sensor 12. In an exemplary embodiment,clamps 44 are similar to hose clamps, having a rotatable worm drivewhich engages a series of slots in the body of the clamp to expand orcontract the diameter of the clamp to secure sensor 12 to body 42 ofretainer 40. In the illustrated embodiment, clamps 44 are passed throughslots formed in retainer body 42 to fix clamps 44 to body 42 and therebyenable fixation of sensor 12 to retainer 40.

In use, magnetic sensor retainer 40 is fixed to sump liquid sensor 12,and magnetically attached to the ferromagnetic material (e.g., steel) oftank manway lid 30 such that retainer 40 holds the sensor 12 in adesired orientation and position. One such desired orientation andposition is a working or monitoring configuration in which the distalend of sensor 12 is positioned in sump 18 adjacent to the bottom of thetank access chamber 22, and the sensor 12 is oriented generally uprightand vertical as illustrated. As described further below, magnetic sensorretainer 40 includes geometry which allows it to be located eitheraround or over top of a tank manway fixing bolt 31. Retainer 40 alsoincorporates geometry to allow an extended extraction tool 50 (FIG. 5)to be used to retrieve sensor 12 from its monitoring configurationwithout requiring an operator to physically enter the tank manway. Inparticular, extraction tool 50 can be used to bring sensor 12 to gradelevel G (FIG. 1) for inspection, maintenance and/or repair. Sensor 12may then be lowered from grade level G and replaced back in its originalposition by tool 50.

As best shown in FIGS. 2 and 3, magnetic sensor retainer 40 includes apair of mounting feet 46 defining an undersurface cavity sized toreceive magnets 48 (FIG. 4). In an exemplary embodiment, the cavitieswithin feet 46 and magnets 48 are sized such that the distal surface ofeach magnet 48 is recessed relative to the adjacent distal surface ofthe foot 46 by a distance R (FIG. 4) when magnets 48 are fully seatedand installed. This recessed configuration protects the material ofmagnet 48 from contact with the metal to which the feet are secured(e.g., the proximal surface of manway lid 30), minimizing or eliminatingthe potential for sparks forming from metal-on-metal contact duringinstallation or removal of sensor retainer 40 to lid 30 or any othermetal surface within tank access chamber 22.

Magnets 48 are secured within the cavities of feet 46 by fasteners 49.In the exemplary embodiment of FIG. 3, for example, each of the pair ofmagnets 48 includes a magnet base 48B with a cannulated boss 48Aextending upwardly therefrom. Boss 48A has a threaded internal aperturefor threadably receiving fastener 49. As illustrated, a fastener 49 isthreaded into boss 48A of each magnet 48 to draw and seat the magnets 48firmly within the cavity defined by feet 46 and against the upper wallthereof. Washers 49A may be interposed between the fasteners 49 and theadjacent surfaces of feet 46 of magnetic sensor retainer 40.

The bottom portion of retainer body 42, including feet 46, is sized tobe positioned at a periphery or lip of a cover or other surface adjacentto sump 18, such as along the periphery of manway lid 30 as shown inFIG. 2. In this way, feet 46 may be securely magnetically fastened tothe surface of the cover 30 while sensor 12 is positioned beyond theperiphery of cover 30, such that sensor 12 can extend downwardly belowthe cover into sump 18 around the bottom of the manway area. Asdiscussed further below, a distal portion of sensor 12 includes a liquidsensor, such as a float, which will be actuated if an unacceptablethreshold level of fluid accumulates within sump 18. In the illustratedembodiment, sump 18 is a relatively small area within tank accesschamber 22 and is positioned and configured to be the first area of thetank access chamber 22 to fill with liquid (e.g., hydrocarbons or water)in the event of a breach of the manway or a leak into sump 18.

In order to facilitate this positioning of retainer 40 and sensor 12,main body 42 of magnetic sensor retainer 40 defines a concave channel orcavity 45 disposed between feet 46. As illustrated in FIG. 2, cavity 45sized to receive the head of a bolt 31, which may be one of the seriesof bolts secured around the periphery of manway lid 30. Feet 46 aresized to be received in the open space between neighboring pairs of suchbolts 31. In this way, the bottom portion of body 42 of retainer 40 fitsaround the head of peripheral bolts 31 of manway lid 30, with such bolts31 not interfering with placement of the bracket flush against the uppersurface of manway lid 30. When flush, the lower surfaces of magnet bases48B may be substantially parallel to the adjacent upwardly facingmounting surface, e.g., the upper surface of manway lid 30.

The bottom portion of body 42 of retainer 40 may also include channel 47formed along a lower surface thereof, as shown in FIGS. 2 and 3. Thischannel 47 is also sized to be received over the head of any nearbybolts, such as bolts 31, without interfering with the flush mounting ofretainer 40 upon the upper surface of lid 30. Channel 47 may be used insome applications where cavity 45 is not compatible with the structuresat the periphery of sump 18, such as installations where the boltpattern or size at the edge of manway lid 30 is not compatible with thespacing and/or sizing of feet 46 and cavity 45.

Body 42 of magnetic sensor retainer 40 includes a raised tool engagementstanchion 43 which extends upwardly from body 42 and defines an aperture43A (FIG. 4) above the adjacent upwardly facing surface of body 42 andwithin stanchion 43. As further described below, the aperture 43A oftool engagement stanchion 43 is sized to receive a corresponding distalportion of an installation/extraction tool 50 which can be used toinstall or remove magnetic sensor retainer 40 from its mounting surfacewithin tank access chamber 22, e.g., the upper surface of manway lid 30.

Magnetic sensor retainer 40 is shown and described in connection withmounting sensor 12 within tank access chamber 22, but it is contemplatedthat similarly constructed magnetic retainers may be used for otherequipment within access chamber 22 as required or desired for aparticular application. For example, FIG. 4A shows a magnetic moduleretainer 240 for retrieving and replacing a secondary containmentmonitoring (SCM) control module 110. Magnetic module retainer 240utilizes similar design features and operational principles as magneticsensor retainer 40 described above, and corresponding structures andfeatures of magnetic module retainer 240 have corresponding referencenumerals to magnetic sensor retainer 40, except with 200 added thereto.However, magnetic module retainer 240 is adapted for use with SCM module110, which occupies an elevated position within access chamber 22relative to liquid sensor 12 as further described below.

SCM module 110 forms a part of a Secondary Containment Monitoring (SCM)system which may be employed in a system of the present disclosure, asfurther described in detail below. SCM module 110 is secured in placeusing magnetic retainer 240 as illustrated in FIG. 4A, with retainerspecifically adapted to interface with manifold 230 (which may besimilar or identical to manifold 111 described above) rather than lid 30as described above. Magnetic module retainer 240 includes two upwardextending walls 242, each with three apertures 245 to engage fasteners244 for securing the SCM module 110 to module retainer 240. The magnets248 (not shown) of module retainer 240 used to secure the SCM module 110in place atop manifold 230 utilize the same structure and configurationof magnets 48 described above, and may be identical. Notably, feet 246are configured to recess the distal surfaces of magnets 248 in the sameway that magnets 48 are recessed by distance R, as described above, toprovide spark protection by preventing magnets 248 from contacting theadjacent surface of manifold 230.

Moreover, it is contemplated that further alternative arrangements ofmagnetic retainer 40 may be utilized in connection with tank accesschamber assembly as required or desired for a particular application, inorder to provide remote accessibility to various system componentswithout requiring the user to physically enter tank access chamber 22 asdescribed herein.

2. Remote Extraction Tool and Method

Referring to FIGS. 5 and 6, extraction tool 50 may be lowered into tankaccess chamber 22 while the operator of the tool remains physically outof the tank access chamber and above grade G (FIG. 1). Extraction tool50 includes an elongated shaft forming handle 52 having a lengthappropriate to the depth of the manway and the vertical distance betweengrade G and sensor 12 (FIG. 1). At the far, or distal, end of the shaft,a magnetic retainer engagement device 54 is attached to handle 52.Engagement device 54 includes a head having an extension or “hook” 56sized to be received in the aperture 43A of stanchion 43 of magneticsensor retainer 40. The head of the extraction tool further includes atleast one foot 58 extending opposite the extension/hook. The foot issized to rest atop the top surface of magnetic sensor retainer 40 fromwhich the tool engagement feature extends. In an exemplary embodiment,the materials chosen for construction of extraction tool 50 arespark-resistant and suitable for use in potentially explosiveatmosphere.

To disengage magnetic sensor retainer 40 from its magnetically-affixedconfiguration at the upper surface of manway lid 30, retainer engagementdevice 54 is lowered through tank access chamber from grade G until hook56 is adjacent retainer 40. Retainer engagement device 54 is then movedsideways (e.g., laterally) to position hook 56 in aperture 43A definedby the stanchion 43 as shown in FIG. 5. Foot 58 is rotated into positionto engage the upper surface of the magnetic sensor retainer 40, whilethe upper surface of hook 56 is engaged with a lower surface ofstanchion 43 within aperture 43A as illustrated.

From the engaged position of FIG. 5, handle 52 of extraction tool 50 isfurther rotated along direction T, as shown in FIG. 6. This rotationprovides a lifting force on stanchion 43 and a counterbalancing downwardforce on the upper surface of retainer 40, which cooperates to form atorque about rotation point P. This torque lifts magnets 48 frommagnetic engagement with manway cover 30, as illustrated, therebyincreasing the distance therebetween and essentially eliminating themagnetic retention force such that sensor 12 can then be freely moved,e.g., upwardly toward grade G. In this way, the geometry of retainerengagement device 54 cooperates with the length of handle 52 ofextraction tool 50 to provide the proper mechanical advantage in theform of a lever to break the magnetic securement of the magnetic sensorretainer 40 to the manway cover 30.

In an exemplary embodiment, the magnets used to hold magnetic sensorretainer 40 in place cooperate to hold the magnetic sensor retainer 40in place with a 35-kilogram pull force needed to dislodge the magnetsfrom their location. This pull force is high enough to prevent removalof the bracket by a direct upward pull, but low enough to allow thesensor to be rotated out of engagement using the leverage of theextraction tool, as described herein. In an exemplary embodiment, handle52 of extraction tool is between 5 feet and 7 feet long in order toprovide adequate length for above-grade access to the distal portion ofa typical tank access chamber 22 having a depth between 3 and 5 feet.

3. Remote Sensor Locator

In addition to, or as an alternative to, the use of magnetic sensorretainer 40 in connection with sump liquid sensor 12, a scoop-shapedremote sensor locator 60 (FIGS. 7-8) may be provided with geometry tofacilitate removal and, in particular, replacement of sensor 12 fromgrade G by use of an elongate control device such as extraction tool 50or a lanyard. The locator 60 guides sensor 12 toward its monitoringposition as sensor 12 is lowered into position from grade G, and mayalso firmly hold sensor 12 in this configuration as further describedbelow.

Referring to FIG. 7, remote sensor locator 60 is accessible from abovegrade G (FIG. 1) and features a “scoop” or funnel-shaped guide cavity62, a mounting portion 64 which is attached to manway lid 30 via one ofthe manway lid bolts 31, and a removable locking arm 66 whichselectively holds sensor 12 in its generally upright and verticalmonitoring configuration. Mounting portion 64 may include a stiffeningrib 65 spanning the gap between the laterally-directed arm connected tobolt 31 and the adjacent wall of the funnel-shaped portion of locator60, in order to provide strength and rigidity to mounting portion 64 andoverall assembly.

At the distal end of guide cavity 62 is an aperture sized to snuglyreceive the corresponding distal end of sensor 12, which is to say theperiphery of the distal end holds the body of sensor 12 firm and fast inthe monitoring configuration and with minimal radial translation (e.g.,a fraction of an inch). The proximal end of guide cavity 62 is sized toreceive the distal end of sensor 12 with substantial clearance. In oneembodiment, the proximal end has a cross-sectional opening area at least3 times the cross-sectional area of the distal end of the sensor 12.Sensor 12 is lowered into the wide proximal opening of guide cavity 62and is gradually directed to a particular position with respect to lid30 by the snug distal fit.

When the sensor is positioned in its monitoring position as shown inFIG. 7, a locking arm 66 fixed to the sensor (e.g., by being affixed tothe exterior of the sensor body at a desired position) is aligned with acorresponding aperture in the proximal rim of sensor locator 60 asillustrated. In particular, a bolt 67 received through a correspondingaperture 68 (FIG. 8) formed in locking arm 66 can be aligned with athreaded aperture 68 in the proximal rim of sensor locator 60 and thebolt 67 received therein to lock sensor 12 in place at a desiredrotational orientation and axial position (e.g., the monitoringconfiguration as described herein). In an alternative embodiment, aquick-release mechanism may be provided in lieu of bolt 67, such as abayonet fitting or the like.

Lanyard 69 may be fixed to the locking arm or the sensor, and may extendupward to or near grade level G in order to facilitate grasping ofsensor 12 from grade level G by an operator, who need not be physicallywithin the manway to raise and lower the sensor. Bolt 67 used to securethe locking arm can be installed or removed by a long tool from abovegrade G, such as a socket wrench with a long extension.

The above-described locator 60 and magnetic retainer 40 can be used forany sensors within the manway, and more than one locator 60 and/ormagnetic retainer 40, or combination thereof, may be used to securemultiple sensors within the manway as required or desired for aparticular application.

In some embodiments of the disclosure, certain sensors may be positionedjust below grade level G within tank access chamber 22 such that thesensors are accessible within the normal (e.g., arms-length) reach of atechnician. If it becomes necessary to access the tank access chamber 22distal of these proximally-mounted sensors, the proximally-mountedsensors can be removed to allow access to distal structures.

4. Automated Sensor Monitoring and Testing

In some embodiments, provision may be made for remote actuation ofsensor 12 such that the sensor is actuated in the same manner as wouldoccur if a threshold level of fluid is present in sump 18. As describedin detail below, such remote actuation may be accomplished with anactuator that pushes a float upwardly within the sensor body, or byrotating sensor 12 upwardly via a pivotable attachment such that thefloat moves within the sensor body under the force of gravity. Whenremotely actuated, verification of proper sensor function may beaccomplished without having to remove sensor 12 from tank access chamber22 or, in some cases, without having to remove lids or expose chamber 22at all. Remote actuation may also be automated by a motor, linearactuator or other suitable controller-connected force generator, suchthat function testing of sensor 12 and the results of such testing maybe integrated into a microprocessor-based monitoring and control system.In an exemplary embodiment, any actuator used within tank 20, includingactuators for remote actuation of sensor 12 as described herein, aresuitable for operation in a potentially explosive atmosphere. Suchactuator may be hydraulic, pneumatic or electrical. In the case ofelectrical actuators, proper provision may be provided for operation ina potentially explosive atmosphere, as may be evidenced by, e.g., ATEXor IECEx certification.

FIGS. 9-25 illustrate various arrangements of testing devices fortesting and verifying the operability of sump liquid sensor 12, such asby manually or automatically actuating sensor 12 from a remote locationoutside of tank access chamber 22. Such a remote location may be at orabove grade G, as shown in FIG. 1, or a control room in the vicinity ofunderground storage tank 100, for example. FIGS. 26-28 are blockdiagrams described to illustrate operation of an embodiment of testingdevice and, more generally, the functionally of testing devicesaccording with the invention. The testing device includes a distalactuator operably connected to sensor 12 and capable of actuating sensor12 in the absence of the threshold level of fluid in sump 18, asdescribed in detail below with respect to various exemplary embodiments.The distal actuator is toggleable between a service configuration and atesting configuration. The toggling of the distal actuator isaccomplished via a proximal control located, in certain configurations,outside tank access chamber 22 and drivingly connected to the distalactuator. In the service configuration, the distal actuator does notinterfere with the regular, in-service operation of liquid sensor 12such that sensor 12 remains in a non-actuated configuration when sump 18is substantially free of liquid and toggles to an actuated configurationif liquid (e.g., hydrocarbons or water) infiltrates sump 18. In thetesting configuration, the actuator physically toggles the sensor 12 tothe actuated configuration even if no liquid is present in sump 18.

As described in detail below, the proximal control may be a manualcontrol (e.g., human-powered) directly mechanically connected to thedistal actuator and selectively toggleable by an operator's applicationof force to the proximal control. Alternatively, the proximal controlmay be an automatic control (e.g., electrically-powered,pneumatically-powered or hydraulically-powered) operably connected tothe distal actuator and mediated by an electronic controller whichtoggles the distal actuator by issuance of a control signal to forcegenerator (e.g., an actuator or motor) which, in turn, is mechanicallyconnected the distal actuator.

Turning now to the illustrative embodiment of FIG. 9, sump liquid sensor12 includes an internal float 120 slideably received within an outershell or housing 122 of sensor 12. Float 120 is designed for axialmotion along the longitudinal axis of sensor 12, and is constrained fromexcessive radial translation by a centrally located guide rod 124received in a correspondingly sized bore through float 120. FIG. 9illustrates sensor 12 in a fully lowered position at the distal end ofguide rod 124, in which a distal surface of float 120 abuts a float stop126 affixed to a distal end of guide rod 124. Float stop 126 has adiameter larger than the bore through float 120 such that float 120cannot advance distally beyond stop 126. In an exemplary embodiment, thefully-lowered position of float 120 defines the non-actuatedconfiguration of sensor 12 as further described below.

Referring to FIG. 1, the distal end of sensor 12 may be placed in sump18 such that the interior of housing 122 is in fluid communication withsump 18. As fluid accumulates in sump 18, fluid also flows into thecavity of housing 122, causing float 120 to advance upwardly along rod124. This upward advancement occurs because float 120 has a density lessthan liquid fluids of interest in sump 18, including diesel fuel,gasoline and water. A switch, such as a magnetic hall effect sensor orany other suitable switch such as a reed switch, proximity sensor, sonarsensor or the like, detects the upward movement of float 120 and sendsan indication, such as a signal, to controller 112 (FIG. 1). When suchdetection has occurred, sump liquid sensor 12 is considered to be the inthe actuated configuration. For purposes of the present disclosure, the“actuated” physical configuration of sensor 12 is the state in whichfloat 120 is toggled to a position corresponding to the presence of anunacceptable level of fluid within sump 18, it being understood thatvarious configurations of the sensor, sump, and switch may be employedas required or desired for a particular application. For example, theswitch may be normally-closed, such that the indication or “signal” sentto controller 112 may be the loss of an electrical connection acrosssensor 12, or may be normally open, such that the indication or “signal”sent to controller 112 is the creation of such an electrical connection.

In an exemplary embodiment, controller 112 is a microprocessor-basedcontroller programmed to determine, based on the “actuated” indicationor signal received from sensor 12, that liquid is present within sump18. Corrective and/or remedial action may then be initiated bycontroller 112, such as activation of an alarm detectable by systemoperators, e.g., electronic notification including internet-basedcommunications such as email, mobile texting, SMS messaging, or thelike. Correction actions may also include activation of fuel shut-offsystems to eliminate further flows of fuel through intake and dischargepipes 14, 16 (FIG. 1) by, e.g., shutting off power to a submersible orsuction pump used for fuel withdrawals. In one particular application,controller 112 may be a computer also responsible for other systemfunctions within the context of a fuel storage and distribution system.One such computer is a tank gauge computer which also monitors thelevel, quality and characteristics of fuel contained within undergroundstorage tank 100. Various fuel storage and distribution systems useablein conjunction with tank access chamber assembly 10 are described infurther detail below. Controller 112 may therefore be located in anysuitable location, generally outside of tank access chamber 22 andremote from assembly 10. Exemplary locations for controller 112 includewithin a service station building near tank 100 or in a separatebuilding or kiosk. Electrical cables between the remote location ofcontroller 112 and assembly 10 may be run through underground electricalconduits 113 sealed to the wall of tank 20. Alternatively, controller112 may be at least partially contained within tank access chamber 22.

In order to ensure proper function of sensor 12 over the service life oftank access chamber assembly 10, it may be desirable to actuate float120 periodically for observation of the function of sensor 12 andcontroller 112, and verification of proper system function upon suchactuation. In some applications, it may be desirable to perform suchtests automatically, i.e., solely by issuance of a command fromcontroller 112 and without operator input. For example, controller 112may be programmed to effect a test of sensor 12 on a regular periodictime schedule, such as weekly, monthly or annually, such that a regulartesting regime can be implemented without requiring consistent operatorinput. In addition to this automatic, controller-mediated testingregime, controller 112 may also be programmed with an override functionwhich allows an operator to effect a test of sensor 12 independently ofthe programmed testing regime. In some applications, further testingfunctionality may be provided in the form of a manual control whichallows the operator to manually operate float 120 without the use ofcontroller 112. Descriptions of exemplary systems which facilitate suchmanual and automated testing of the function of sensor 12 follow, withreference to one or more of FIGS. 9-25.

In FIG. 9, sensor 12 is equipped with a generally vertical pull rod 128disposed between the outer perimeter of float 120 and the adjacent innerperimeter of housing 122. Pull rod 128 extends downwardly from aproximal location, across the axial extent of float 120, and terminatesat a distal end. At the distal end of pull rod 128, a radial protrusion130 extends radially inwardly such that protrusion 130 is positionedunderneath float 120 as illustrated. When rod 128 is urged in a proximaldirection by force F1, radial protrusion 130 engages a distal surface offloat 120 and pulls float 120 upwardly along guide rod 124 to physicallylift float 120 into an actuated position, even if no substantial amountof fluid is present in sump 18.

As further discussed in detail below, force F1 for actuation of pull rod128 may be provided by force generator controllable by controller 112.The motive force for the force generator, (e.g., the actuator or motor)can be electric, pneumatic or hydraulic, including hydraulic forcegenerators powered by fuel under pressure or vacuum from a submersiblepump, or dispenser pump used for fuel delivery via discharge pipe 16, ora pump-driven vacuum generator such as a submersible pump venturi. Thismotive force may be actuated by a solenoid or similar control/driverinterface such that a signal from controller 112 can selectivelyactivate the actuator or motor to drive pull rod 128 upwardly ordownwardly. As noted above, a test controller, which may be integratedinto controller 112 or may be a separate controller, may activate theforce generator pursuant to programming (e.g., for regular periodictesting of sensor function) or pursuant to a manual command by a systemoperator, such as a push button. In addition, pull rod 128 may providefor manual actuation by an operator, e.g., by having a proximal endaccessible from above grade G to allow the operator to manually graspthe proximal end and pull up float 120 by hand.

Turning now to FIG. 10, an alternative arrangement is illustrated inwhich radial actuator 134 passes through a slot 132 formed in thesidewall of housing 122 of sensor 12. As illustrated, radial actuator134 is positioned to engage the distal surface of float 120 at one endand plunger 138 of a force generator, illustratively linear actuator136, at the opposing end. Actuator 136 may be actuated, e.g., bycontroller 112, such that actuator 136 generates force F2 to extendplunger 138 outwardly. This pushes radial actuator 134 and float 120upwardly. In this way, sensor 12 may be toggle from its non-actuatedconfiguration to its actuated configuration by actuator 136, which mayin turn be operably connected to controller 112 as described herein.

Turning now to FIG. 11, yet another remote actuation system isillustrated in which plunger 138 of actuator 136 is placed directlyunderneath float 120, such that actuation of actuator 136 (e.g., bycontroller 112) directly forces float 120 to advance upwardly as plunger138 extends outwardly. In the illustrated embodiment, an intermediatecontact plate 140 may be affixed to the end of plunger 138 in order toprovide desired surface contact characteristics (e.g., surface pressure)between plunger 138 and float 120.

FIG. 12 illustrates an exemplary embodiment of a cable-operated sensortester 70 utilizing a Bowden cable type actuator having a stationarycable sheath 72 surrounding a removable cable core 74. In theillustrated embodiment, sensor 12 is fixed to framework 142 via collar144. Framework 142 may be connected to manway lid 30 (FIG. 1) in anysuitable fashion, or, in the alternative, sensor 12 may be fixed to lid30 via magnetic sensor retainer 40 as shown in FIG. 2 and described indetail above.

Cable-operated sensor tester 70 terminates at an upwardly facing distalend shown in FIG. 13. Sheath 72 descends from a proximal end downwardlyinto sump 18 (FIG. 1), and its distal end turns to ascend upwardly intothe cavity of sensor housing 122. In a non-actuated configuration,pressure plate 76 affixed to the distal end of cable core 74 is in alowered position abutting cable sheath 72. When cable core 74 is axiallyadvanced through sheath 72 by force F3 as shown in FIG. 14, pressureplate 76 advances upwardly, pushing float 120 away from its non-actuatedposition abutting (or adjacent to) float stop 126′ in a proximaldirection such that sensor 12 is actuated into its actuated/testposition. Advantageously, the proximal end of cable-operated sensortester 70 may be terminated at any desired location and position, suchas above grade G or at a remote location within tank access chamber 22.

The proximal end of cable core 74 may be operably connected to a forcegenerator such as a linear actuator or motor, which can be controlled bycontroller 112 to selectively generate force F3 upon command. Exemplaryforce generators may include a motorized winding drum having core 74wound therearound, or a linear actuator plunger which acts directly uponthe proximal terminal end of cable core 74. Such a motor or actuator maybe pneumatic, electric or hydraulic, for example, as described infurther detail herein. Alternatively or in addition to theelectronically controllable force generator, a manual override actuatormay be provided so an operator may manually push and/or pull on cablecore 74 to actuate sensor 12.

FIG. 15 illustrates another testing arrangement amenable to manualand/or automated actuation. Swingarm-operated sensor tester 80 includesupright stanchion 82 fixed (e.g., by bolts, welding or a magneticbracket, such as magnet sensor retainer 40 described herein) to manwaylid 30 and extending upwardly therefrom. Swingarm 84 is rotatablyattached to stanchion 82 and extends radially outwardly from manway lid30 over sump 18 as shown. Sensor 12 is clamped or otherwise fixed uponswingarm 84, such that the distal end of sensor 12 extends downwardlyinto sump 18 in the monitoring configuration of tester 80 illustrated inFIG. 15. In an exemplary embodiment, a moveable magnet 86 is fixed toswingarm 84 and an opposite polarity fixed magnet 88 is fixed tostanchion 82. When swingarm 84 is in the monitoring configuration (e.g.,substantially horizontal as shown), magnet 86 is magnetically engagedwith magnet 88 to create an attraction force therebetween, therebycreating a force which urges swingarm 84 to remain stationary in themonitoring configuration shown in FIG. 15.

When it is desired to test the function of sensor 12, force F4 isapplied to pull cord 78, which is affixed to the radially outward end ofswingarm 84 as shown in FIGS. 15 and 16. Force F4 is sufficient toovercome the magnetic attraction force between magnets 86, 88, and liftswingarm 84 and sensor 12 upwardly as shown in FIG. 16. As sensor 12reaches a horizontal position as shown in FIG. 16, the force of gravitytending to maintain float 120 (FIG. 9) and the distal position iseliminated. Further pivoting of sensor 12 via swingarm 84, such that thesensor is at least partially inverted (i.e., the distal end of sensor 12is placed higher than its proximal end), causes gravity to urge float120 proximally along guide rod 124 (see, e.g., FIG. 9), therebyactuating sensor 12 without the presence of liquid in sump 18. When thetest is complete, force F4 may be reversed or eliminated, allowingswingarm 84 and sensor 12 to return from the test position to themonitoring position (FIG. 15).

FIGS. 17 and 18 show another swingarm-operated sensor tester 80A similarin structure and function to tester 80 described above. Correspondingreference numerals in tester 80A describe similar structures to tester80, except with the letter “A” appended there to indicate a differencein structure or function from the corresponding structure of tester 80.

For example, swingarm 84 is retained in the monitoring configuration ofFIG. 17 not by magnets, but rather by extension spring 86A which isrotatably fixed to both stanchion 82 and swingarm 84 as illustrated. Asswingarm 84 is lifted by tension and pull cord 78 as described above,extension spring 86A is elongated and reaches a maximum elongation whenpivot point 87 on swingarm 84 is directly above pivot point 89 onstanchion 82. Thereafter, as swingarm 84 continues to pivot into thetest configuration of FIG. 18, spring 86A is allowed to slightlycompress such that spring 86A urges swingarm 84 to remain in the testconfiguration until dislodged therefrom by a force F5. In theillustrated embodiment, the final test configuration is defined byswingarm stop 88A which contacts swingarm 84 at the desiredconfiguration.

Advantageously, the swingarm-operated sensor testers 80, 80A operated bypull cord 78 are amendable to automated or manual actuation as requiredor desired. For example, pull cord 78 may have a proximal end abovegrade G (FIG. 1) which is easily accessible to service personnel formanual application of forces F4 and F5 in a testing procedure. In such amanually-actuatable embodiment, pull cord 78 may be stowed beneath gradelid 106 and/or subgrade lid 104 for protection during normal service,and retrieved by removal of lids 106 and/or 104 for actuation.

Alternatively or in addition to the manually-operable pull cord 78, thesame or a different cord 78 may be coupled to an actuator operablyconnected to controller 112 (FIG. 1), such as a motorized winding drum,or linear actuator powered by a pneumatic, hydraulic or electrical powersource as described above with respect to cable-operated tester 70. Suchan actuator may be placed, for example, within tank access chamber 22 ata suitable location above swingarm-operated sensor tester 80, 80A toimpart a desired direction and magnitude for forces F4 and F5. To theextent that the directionality of forces F4 and F5 may vary depending onthe particular location and configuration of swingarm 84 and thepotential for variable force directions in connection with thetest-position and monitoring-position biasing forces provided by spring86A, two actuators may be used each with a separate pull cord 78.Alternatively, the relative vertical position of pull cord 78 abovetester 80A may be moved by translating the actuator between twopositions within tank access chamber 22 or translating an idler pulleybetween two such positions, for example.

Turning now to FIG. 19, cam-operated sensor tester 90 is illustrated asanother option for automatically reconfiguring sensor 12 between amonitoring position and a test position. Tester 90 includes uprightstanchion 92 with sensor housing 94 pivotably connected thereto aboutlongitudinal axis A. As described in further detail below, sensor 12extends through an aperture formed in sensor housing 94 with thelongitudinal axis of sensor 12 substantially perpendicular to rotationalaxis A, such that rotation of housing 94 rotates sensor 12 from itsmonitoring position (shown in FIG. 19) to a test position (shown in,e.g. FIG. 23). In the partially inverted test position, float 120 (FIG.9) is allowed to translate under the force of gravity to its actuatedposition, similar to the operation of the test positions described abovewith respect to swingarm-operated sensor testers 80, 80A.

Cam shaft 96, shown in FIGS. 19 and 20, passes through upright stanchion92 (FIG. 19) and into a central bore formed through housing 94 (FIG. 20)generally perpendicular to the housing bore which receives sensor 12.Housing 94 is rotatably supported upon cam shaft 96, via retainer ring95. Housing 94 also rotates with respect to stanchion 92, with a lowfriction bearing 97 optionally provided there between in order tofacilitate rotation. In an exemplary embodiment, cam shaft 96 is rotatedby motor 98, which is fixed to stanchion 92 as illustrated. As withother embodiments described herein, motor 98 may be electricallypowered, pneumatically powered, or hydraulically powered, for example.As described further below, motor 98 may be a stepper or servo-typemotor suitable for precise rotational positioning of cam shaft 96 withless than one full rotation of the motor mandrel in normal operation.

For electric motors used in sensor testers contained within tank accesschamber 22 as described herein, the motors may be a sealed bearing typebearing an ATEX or IECEx designation signifying approval for use in apotentially explosive atmosphere. Thus, such electric motors may be usedin areas where fuel or fuel vapor may be present, such as tank accesschamber assembly 10 used in conjunction with an underground fuel storagetank 100 as shown in FIG. 1.

FIG. 19 illustrates stanchion 92 supported on lid 30 by magnetic sensorretainer 40, as shown in FIGS. 1-5 and described in detail above. Forsimplicity, only stanchion 92 is shown to be supported magnetic sensorretainer 40 but it is contemplated that any of the sensor testersdescribed herein may be supported by magnetic sensor retainer 40 asrequired or desired for a particular application. Moreover, combiningsensor retainer 40 with an automatically testable sensor tester such astesters 70, 80, 80A, 90 or 90A provides complementary benefits in thecontext of tank access chamber assembly 10 (FIG. 1) and the undergroundfuel storage system of which it forms a part. For simplicity, theinteraction between such testers and magnetic sensor retainer 40 will bedescribed with respect to tester 90 alone, it being understood that suchinteraction is equally applicable to any sensor tester design within thescope of the present disclosure.

Upon activation of sensor tester 90, sensor 12 may fail to actuate,i.e., sensor 12 may fail the test for which tester 90 is designed. Ifsuch a failure occurs, controller 112 may alert an operator as notedherein, and the next step in the protocol may then be to retrieve thesensor for manual inspection and potential repair or replacement.Similarly, it may be determined for other reasons that sensor 12requires manual (i.e. physical) inspection by an operator directly, suchas a time delay after actuation of tester 90 and before actuation ofsensor 12. As described in detail above, magnet sensor retainer 40 andextraction tool 50 facilitate such a retrieval process, as well aseventual re-installation of a new or repaired sensor 12 within tankaccess chamber 22.

Turning to FIG. 20, cam shaft 96 is shown received within the centralbore of housing 94 with clearance, such that cam lobe 190 and cam key192 may rotate freely therein. In addition, the central bore throughhousing 94 includes notch 194 which interacts with key 192 to rotatesensor 12 from the monitoring position to the test position as furtherdescribed below.

Sensor 12 is biased into the illustrated monitoring position by torsionspring 196, illustratively positioned within the bore of housing 94 andcoiled around cam shaft 96. Torsion spring 196 is arranged to urgerotation of housing 94 relative to cam shaft 96 until movable stop 198coupled to housing 94, contacts fixed stop 199 coupled to stanchion 92.In this way, torsion spring 196 cooperates with stops 198, 199 to definethe generally upright and vertical configuration of sump liquid sensor12 associated with the monitoring configuration of cam-operated sensortester 90.

When it is desired to rotate sensor 12 away from the monitoring positionand into the test position, motor 98 may be actuated to rotate cam shaft96 relative to housing 94. As shown in FIG. 21, cam shaft 96 starts froma rotational position in which neither cam lobe 190 nor key 192 engagesthe inner bore of housing 94 with any significant force. In thisconfiguration, sensor 12 is in its fully deployed position at the bottomof sump 18 (FIG. 19) and is in a generally upright and verticalconfiguration. As motor 98 rotates cam shaft 96 in a clockwise directionfrom the perspective of FIG. 21, an intermediate configuration isachieved as shown in FIG. 22. In this configuration, cam lobe 190engages the wall of the central bore of housing 94 such that housing 94is lifted upwardly. Key 192 is not yet in any significant forcetransferring relationship with housing 94. The upward lift of housing 94provided by cam lobe 190 elevates the distal end of sensor 12 withinsump 18, as illustrated in FIG. 22, such that sensor 12 is ready to berotated away from its monitoring position without risking any damage tothe distal end of sensor 12.

Next, as cam shaft 96 continues to rotate in a clockwise direction fromthe perspective of FIG. 22, key 192 advances toward and eventuallyengages the correspondingly formed notch 194 within the bore of housing94. Further rotation of cam shaft 96 rotates housing 94 and sensor 12about longitudinal axis A (FIG. 19) and lifts the distal end of sensor12 out of sump 18. As rotation continues to the partially invertedconfiguration of FIG. 23, the distal end of sensor 12 is rotated to beabove the proximal end of sensor 12, such that float 120 may axiallyadvance toward the actuated position within sensor 12 under the force ofgravity as described in detail above. When so advanced, actuation ofsensor 12 occurs without the presence of an unacceptable amount of fluidin sump 18 and the testing procedure is complete.

To move the sensor 12 from the test configuration of FIG. 23 back to themonitoring configuration of FIG. 21, rotation of cam shaft 96 is simplyreversed to the counter-clockwise direction, allowing sensor 12 andhousing 94 to rotate under the force of torsion spring 196 (FIG. 19)back to the substantially upright and vertical position of FIGS. 19 and21.

Turning now to FIGS. 24 and 25, a second rotatable sensor tester 90A isshown. Tester 90A is similar in overall structure and function to tester90 described above, in that a central shaft 96A pivotably attachessensor 12 to upright stanchion 92A via sensor housing 94A. Tester 90Autilizes similar design features and operational principles as tester 90described above, and corresponding structures and features of tester 90Ahave corresponding reference numerals to magnetic tester 90, except with“A” added thereto.

However, shaft 96A does not utilize cam-on-lobe or key-on-notcharrangements as described above with respect to sensor tester 90, butrather, shaft 96A is simply rotatably connected to housing 94A. Also, inthe illustrated embodiment, cable 98A is used to rotate housing 94Arelative to stanchion 92A, rather than motor 98 as described above. Itis contemplated that motor 98 can be used in conjunction with tester90A, and that cable 98A can be used with tester 90, consistent withtransferability of drive mechanisms among the various tester designs asdescribed herein.

Generally speaking, torsion spring 196A biases sensor 12 and housing 94Ainto the generally upright and vertical monitoring configuration shownin FIG. 24. When cable 98A is pulled with force F6, the wrap of cable98A around the generally cylindrical outer surface of housing 94A causeshousing 94A to rotate against the biasing force of spring 196A to liftand rotate sensor 12 away from the monitoring position toward a testposition. Referring to FIG. 25, it can be seen that the axis of rotationAl of housing 94A is laterally offset with respect to the longitudinalaxis of the generally cylindrical sensor 12. Thus, when force F6 isapplied to cable 98A, sensor 12 is not only rotated away from itsvertical configuration but also lifted at the distal end thereof awayfrom the bottom of sump 18 (FIG. 24). This offset configuration protectsthe distal end of sensor 12 during the reconfiguration of the systembetween the monitoring and testing configurations.

Turning now to FIGS. 26-28, a control modality for remote monitoring andtesting of the function of sensor 12 is illustrated. For simplicity, thecontrol system is shown and described with reference to liquid reservoir300 and associated structures, it being understood that such structuresmay correspond to the analogous structures of assembly 10 described indetail above. For example, liquid sensor 12 may be identical to, orcompatible or interchangeable with, liquid sensor 310. Similarrelationships may exist for tank 20 and reservoir 300, controller 112and controller 320, float 120 and floating element 316, the varioustesters described above and testing device 340, and tank access chamberand liquid chamber 306. Similarly, distal actuator 342 may be identicalto, or interchangeable or compatible with, the distal portions (i.e.,portions contained within chamber 22) of the various testers describedherein, while proximal control 344 may be identical to, orinterchangeable or compatible with, the proximal portions (i.e.,portions outside of chamber 22) of the various testers described herein.

FIGS. 26-28 illustrate operation of a liquid sensor 310 coupled to atesting device 340 and operable in a liquid reservoir 300 to detect aliquid 308. FIG. 26 depicts liquid 308 at a threshold level, i.e., insufficient quantity to cause a level indicator 322 to emit a liquidpresence indication 324. FIG. 27 depicts liquid 308 below a thresholdlevel, i.e., in a quantity insufficient to cause level indicator 322 toemit liquid presence indication 324 (which, accordingly, has beenomitted from FIG. 27). In both instances testing device 340 isconfigured in a service configuration. FIG. 28 depicts liquid 308 belowthe threshold level, in a quantity insufficient to cause level indicator322 to emit liquid presence indication 324, but with testing device 340configured in a testing configuration, such that level indicator 322 isshown emitting liquid presence indication 324. This is the same basicfunctional modality which allows testers in accordance with the presentdisclosure, including testers 70, 80, 80A, 90 or 90A, to selectivelyactuate sensor 12 even when no liquid is present at or above a thresholdlevel within sump 18. The abovementioned structure and relatedfunctionalities are described in more detail below.

Liquid reservoir 300 comprises an access chamber 302 and a liquidchamber 306 adjacent thereto which may contain liquid 308. A levelthreshold detectable by liquid sensor 310 is indicated by a level line318. Liquid sensor 310 comprises detection logic 312 and a detectiontransducer 314 comprising a floating element 316. Detection logic 312 isconfigured to detect and output a level indication when floating element316 reaches the level threshold. A controller 320 receives the levelindication and outputs a level signal to a level indicator 322. Uponreceipt of the level signal, level indicator 322 emits liquid presenceindication 324. In variations of the present embodiment detection logic312 forms part of controller 320. In variations of the presentembodiment detection logic 312 and level indicator 322 form part ofcontroller 320. In variations of the present embodiment controller 320,and any variations thereof, is positioned outside access chamber 302. Asshown, detection logic 312 is positioned within liquid chamber 306.

Testing device 340 comprises a distal actuator 342 and a proximalcontrol 344. Distal actuator 342 is positioned, at least in part, withinliquid chamber 306. Proximal control 344 is positioned outside liquidchamber 306 and, preferably, outside access chamber 302, such that auser may actuate proximal control 344 without entering or access chamber302 to actuate testing device 340. As shown, distal actuator 342comprises a distal end of a control wire coupled to floating element 316and proximal control 344 comprises a proximal end of the control wire. Auser may thus pull on the control wire (or may program or direct acontroller, such as controller 112, to actuate a force generator to pullon the control wire) to lift floating element 316 and cause levelindicator 322 to emit liquid presence indication 324, as shown in FIG.28. Testing device 340 may comprise any of the actuation mechanismsdescribed above and liquid sensor 310 may comprise any of the liquidsensors described above, such as liquid sensor 12.

Detection logic may be comprised by liquid sensor 310 or incorporated incontroller 320. The term “logic” as used herein includes software and/orfirmware executing on one or more programmable processors,application-specific integrated circuits, field-programmable gatearrays, digital signal processors, hardwired logic, or combinationsthereof. Therefore, in accordance with the embodiments, various logicmay be implemented in any appropriate fashion and would remain inaccordance with the embodiments herein disclosed. A non-transitorymachine-readable medium comprising logic can additionally be consideredto be embodied within any tangible form of a computer-readable carrier,such as solid-state memory, magnetic disk, and optical disk containingan appropriate set of computer instructions and data structures thatwould cause a processor to carry out the techniques described herein. Anon-transitory machine-readable medium, or memory, may include randomaccess memory (RAM), read-only memory (ROM), erasable programmableread-only memory (e.g., EPROM, EEPROM, or Flash memory), or any othertangible medium capable of storing information.

5. Other System Components

Various other system components and subsystems may be integrated withaccess chamber assembly 10 for complementary functions. Exemplarysystems combinable with access chamber assembly 10 in the context of acomprehensive, redundant and safe underground fuel storage system arefurther described below.

A remote viewing system may be used to monitor remote installation,removal and/or actuation of sensor 12, each of which is described indetail above. The viewing system may include, for example, a videocamera which monitors the interior of tank access chamber 22 and isviewable from a remote location, e.g., a control room. Via the videofeed provided by the video camera, a station operator can view remoteactuation of sensor 12 and visually verify proper placement into thetest and/or monitoring configurations as described in detail above.Further details of an exemplary remote viewing and verification systemcan be found in International Patent Application Publication No. WO2016/025456, entitled MONITORING SYSTEM FOR A REFUELING STATION andfiled Aug. 11, 2015, the entire disclosure of which is hereby expresslyincorporated herein by reference.

Tank 20 may be formed from leak-resistant polyethylene, such as byforming two tank halves and joining the halves together by electrofusionwelding to form tank 20 with tank access chamber 22. In this embodiment,the two halves form one homogeneous part after welding. Alternatively asshown in FIG. 1, tank access chamber 22 may be formed from a base panel36 which is attached to a tank collar or sidewall 38 rising from basepanel 36. Base panel 36 and sidewall 38 may be fused in a watertightmanner, such as by electrofusion. The polyethylene tank 20 which definesthe tank access chamber 22 is configured to allow access from aboveground to a tank manway, within the watertight tank access chamber 22defined by the tank 20. The tank forming the tank access chamber can besealed, e.g., to manway riser 26 and/or to a tank collar 24 ofunderground storage tank 100 such that a leak from the manway iscontained in the tank access chamber 22. Any liquid from such a leakwill accumulate in sump 18 and be detected by sensor 12 as described indetail above.

Electrofusion entry seals may also be employed to allow pipes and cableducts, including fuel intake pipe 14 and fuel discharge pipe 16 shown inFIG. 1, to penetrate the wall of the tank 20 and enter into the tankaccess chamber 22. Such entry seals may weld to both the ducts and/orpipes (e.g., pipes 14, 16) and the material of tank 20 such that thepipes and electrical ducts become one homogeneous part together with thepolyethylene tank 20, while also being sealed against ingress of groundwater. Exemplary entry seals suitable for use in conjunction withsystems of the present are described in International Patent ApplicationNumber PCT/US2015/042450, co-owned with the present application, whichwas filed Jul. 18, 2015 and is entitled ELECTRIC TRANSITION CHAMBER, theentire disclosure of which is hereby expressly incorporated herein byreference. Vapor seals for sealing cable ducts to cables in an airtightmanner may also be employed to stop the transfer of vapors into or outof the tank chamber 22.

An overfill prevention valve (OPV) may be fitted into a filling pipeextending into the underground polyethylene tank 20, such as fuel intakepipe 14. The OPV provides a valve actuation (e.g., a mechanical valveactuation) when the tank is filled past a certain level, reducing theflow into the tank to a low level to allow draining of the tanker fillline which feeds intake pipe 14. Exemplary OPVs suitable for use withthe system of the present disclosure are described in U.S. PatentApplication Publication No. 2014/0076421, filed Sep. 13, 2013 andentitled OVERFILL PREVENTION VALVE, and U.S. Patent ApplicationPublication No. 2015/0240966, filed Aug. 27, 2015 entitled DROP TUBESEGMENT, the entire disclosures of which are hereby expresslyincorporated herein by reference. Such an OPV system may further includea removable filling line riser cap positioned above the OPV which can beremoved and re-fit using an extended tool, such as extraction tool 50described in detail above. In particular, hook 56 and/or foot 58 ofextraction tool 50 may be engaged with an exemplary filling line risercap and used to manipulate the cap without the need for the operator tophysically enter the tank access chamber 22.

In another embodiment, operation of such an OPV may be manually effectedby use of a tool with extended handle and a magnetic lifting head, whichcan be inserted into the filling line from above without the need forthe operator to physically enter the tank access chamber 22. In thisway, operation of the OPV can be validated. Examples of an OPV withremote testing for use with the present disclosure can be found in U.S.Patent Application Publication No. 2015/0192220, filed Jan. 2, 2015 andentitled OVERFILL PREVENTION VALVE WITH REMOTE TESTING, the entiredisclosure of which is hereby expressly incorporated herein byreference.

As noted above, secondary containment control module 110 and manifold111 may be used in connection with a monitoring system, which in turn isfluidly connected to one or more evacuated interstitial spaces indouble-wall containment structures, such as underground storage tank100, pipes 14, 16, and spill containment units (not shown). Exemplarysecondary containment systems are disclosed in U.S. Pat. No. 8,069,705,filed Jul. 20, 2009 and entitled “Method and apparatus for continuouslymonitoring interstitial regions in gasoline storage facilities andpipelines,” and in U.S. Pat. No. 8,684,024, filed Oct. 14, 2010 andentitled “Spill Containment System,” the entire disclosures of which arehereby expressly incorporated herein by reference.

While the present disclosure has been described as having exemplarydesigns, the present disclosure can be further modified within thespirit and scope of this disclosure. This application is thereforeintended to cover any variations, uses or adaptations of the disclosureusing its general principles. Further, this application is intended tocover such departures from the present disclosure as come within knownor customary practice in the art to which this disclosure pertains.

1-27. (canceled)
 28. A method of assessing a function of a sensor, themethod comprising: installing a sensor in a sump of a fuel dispensingsystem, such that the sensor extends downwardly into the sump to monitorfor fluid infiltration of into the sump; and after installing, assessingthe function of the sensor without physically accessing the sump. 29.The method of claim 28, wherein said assessing comprises actuating afloat within the sensor without the presence of liquid in the sump. 30.The method of claim 29, wherein said actuating the float comprisesmanually actuating the float by toggling a proximal control from abovegrade.
 31. The method of claim 29, wherein said actuating the floatcomprises automatically actuating the float by toggling a proximalcontrol from above grade.
 32. The method of claim 31, wherein saidtoggling comprises issuing a command from an electronic controller. 33.The method of claim 29, wherein said actuating the float comprises atleast partially inverting the sensor such that the float movesproximally under the force of gravity.
 34. The method of claim 29,wherein said actuating the float comprises raising the float viaengagement of a lifting mechanism with the float.
 35. The method ofclaim 28, wherein the sensor is located in a tank defining a tankchamber the sump formed at the bottom of the tank chamber, the methodfurther comprising: determining that the sensor requires manualinspection by an operator based on assessing the function of the sensor;accessing the sump from above grade; retrieving the sensor withoutphysically entering the tank chamber.
 36. The method of claim 35,wherein said determining comprises determining that the sensor hasfailed to actuate.
 37. The method of claim 35, wherein said determiningcomprises: lowering an extraction tool having a retainer engagementdevice at a distal end thereof into the tank chamber from grade level;engaging the retainer engagement device with a magnetic sensor retainerfixed to the sensor; dislodging the magnetic sensor retainer from thetank chamber by using the extraction tool to disengage the magneticengagement between the magnetic sensor retainer and an adjacentferromagnetic surface; and using the extraction tool to raise themagnetic sensor retainer and the sensor out of the tank chamber.
 38. Themethod of claim 37, wherein said dislodging comprises rotating theextraction tool to provide a lifting force on a stanchion of themagnetic sensor retainer, and to provide a counterbalancing downwardforce on an upper surface of the magnetic sensor retainer, whichcooperates to form a mechanical advantage sufficient disengage themagnetic engagement between the magnetic sensor retainer and theadjacent ferromagnetic surface. 39-50. (canceled)
 51. A method ofassessing a function of a sensor retained within in a tank defining atank chamber of a fuel dispensing system by a sensor retainer, such thatthe sensor extends downwardly into a sump formed at the bottom of thetank chamber to monitor for fluid infiltration into the sump, the methodcomprising: accessing the sump from above grade; lowering an extractiontool into engagement into the tank chamber from grade level until adistal end of the extraction tool engages the sensor retainer;connecting the extraction tool to the sensor retainer; and retrievingthe sensor without physically entering the tank chamber by raising theextraction tool, the sensor retainer and the sensor.
 52. The method ofclaim 51, further comprising installing the sensor back to its locationin the tank chamber of the tank without physically accessing the tankchamber.
 53. The method of claim 51, further comprising: assessing thefunction of the sensor without physically accessing the sump; anddetermining that the sensor requires manual inspection by an above-gradeoperator based on assessing the function of the sensor.
 54. The methodof claim 53, wherein said step of determining comprises determining thatthe sensor has failed to actuate.
 55. The method of claim 51, whereinthe sensor retainer is a magnetic sensor retainer fixed to the sensor,and wherein: said step of connecting comprises engaging the extractiontool with the magnetic sensor retainer; said step of retrieving thesensor comprises dislodging the magnetic sensor retainer from the tankchamber by using the extraction tool to disengage the magneticengagement between the magnetic sensor retainer and an adjacentferromagnetic surface, and then using the extraction tool to raise themagnetic sensor retainer and the sensor out of the tank chamber.